The invention relates to a road brine spreader for driving along a road or a similar carriageway and within a border area, such as a roadside, under pressure spreading brine out over the road via a number of liquid nozzles.
In many countries, it is a perpetually recurrent problem that the friction of the roadway surfaces is reduced substantially by ice and snow when the temperature falls below freezing point. Thereby, the roads become slippery and dangerous to drive on to the wheeled traffic.
A very widespread method to reduce the risk of traffic accidents on icy roads consists in spreading brine over the roadways from a vehicle with a rotating plate for spreading the brine.
It has turned out that less brine can be used with the same result when it is spread in an aqueous solution. For this purpose, a road brine spreader can advantageously be used which, just as field sprayers, operates with liquid nozzles for, under pressure, spreading the water over the roadways. The liquid nozzles are conventionally of the kind which spray the brine out in a conical form whereby the water is evenly and uniformly spread across the roadway. On the other hand, it is difficult or almost impossible to avoid that brine is also spread beyond the border areas which thereby risk being more or less damaged. Thus, grass and plants on sides or edges of ditches along the roads can hardly stand being sprayed by brine, which furthermore constitutes an additional cost of the brining of the roadway proper.
The object of the invention is to provide a road brine spreader of the kind mentioned in the opening paragraph whereby brine can be spread evenly and uniformly over an iced up and/or snowed up roadway without at the same time being spread over the border areas.
The novel and unique features according to the invention, whereby this is achieved, is the fact that the nozzles are arranged to send out water in the form of jets, and that the sprayer has a control system comprising regulation means for altering the water pressure and/or quantity and/or the angular position of at least some of the nozzles, and actuating means for actuating the regulation means.
The water jets form a concentrated water flow that easily and securely can be effectively controlled so that it is only the actual roadway which is hit by the jets. The border areas are therefore kept clear of brining. On meeting the roadway, the jets furthermore splash out so that the water is evenly spread over the roadway.
In an advantageous embodiment, there can, on each side of the road brine spreader, be placed an elongated side manifold each having a number of side nozzles for sending out water jets transversely to or slantwise of the direction of travel of the sprayer, and when the side manifold furthermore is pivotally mounted, the sprayer is, with a suitable manual or automatic control, able to send out water jets exactly to the roadside and no further.
When the angle formed by the direction in which the side nozzles send out jets and a horizontal plane is increasing nozzle by nozzle along the side manifold, the liquid jets hit the roadway in an evenly spread manner in a zone extending inwards from the border area.
The above control can advantageously be achieved by means of an automatically functioning control system which comprises a preprogrammed computer and different kinds of detectors for registering the parameters which, while driving along the road, affect the spraying process and as input to the computer, form the basis of computation of output for making the actuating means of the sprayer actuate the regulation means for optimum regulation of the different operating parameters of the sprayer.
The detectors can be of any suitable kind, such as laser detectors, ultrasonic detectors, or camera detectors. The wanted input for the computer can also come from a live wire which is lying along the roadside and is sending current to an ammeter when the outermost water jet gets too close to the wire.
Furthermore, the computer can expediently be arranged to store input received during driving in one direction and use these input to form output for optimum regulation of the operating parameters when driving in the opposite direction.
Finally, it is an advantage when the control system comprises a Global Position System (GPS) for via a satellite registering the character of the present position of the vehicle. Thereby, the spreader is enabled to automatically adapt the spread brine quantity to the local conditions which e.g. might be a bridge, a curve, or a stretch of forest.
It is furthermore an advantage when the control system comprises measuring of the resultant wind velocity and direction for regulation of the different operating parameters in order to thereby compensate for the effect of the resultant wind velocity on the course of the spreading.